It's hardly news that divorces between wealthy people can be messy. A court in 1848 considering the separation of a wealthy, landowning woman called Mary Wilson, and her barrister husband John for example, was forced to trawl through the unfortunate details of his alleged impotence and failure to consummate the marriage. She meanwhile decided to move in with her lawyer. Mrs Wilson obviously received excellent legal advice because her husband's attempts to obtain a maintenance payment of £1,500 a year – a lot of money in those days – came to nothing.

In those days the courts did not even have the power to grant a divorce – that came with a new law in 1857. Instead the Wilsons had to claim "nullity of marriage" on the grounds of impotence.

But the next major case on the subject, in 1929, has been surprisingly durable. It set a tone which has persisted among judges; in the words of Lord Atkin "the wife's right to future maintenance is a matter of public concern, which she cannot barter away."

In that case, a woman called Mrs Hyman obtained a divorce from her adulterous husband. He tried to limit the amount of maintenance he had to pay her to the terms of an agreement they had entered into during the marriage. The court disagreed, taking a view which is often described as "paternalistic".

The unwillingness of the UK's courts to enforce prenups seems to have two underlying motives. One, judges value reasonableness above the terms of private agreements, and are offended by divorce settlements which seem to weight the division of wealth unfairly in favour of one party. And two, they are concerned that allowing one partner, usually a woman and possibly children too, to fall into poverty, would face an increased burden on the state.

"It is in the public interest that the wife and children of a divorced husband should not be left dependent on public assistance or on charity when he has the means to support them," said Lord Denning, in another famous divorce case Bennett v Bennett in 1952.

It's hard to imagine the courts radically changing that approach. There is more to divorce than the terms of a private contract – the welfare, fairness and financial stability of divorcing spouses and their children is firmly in the bounds of public policy too.

But things are becoming more complicated. The internationally wealthy are choosing the English high court as their jurisdiction of choice, leaving this country's courts with the headache of what to do with contracts that would automatically be binding in the country in which they were signed.

This week the supreme court is deciding the long-running case of a German heiress and her French ex-husband, and whether their prenup should be enforced. Katrin Radmacher is a wealthy woman; she has shares in a family company worth around £50 million, and further assets of around £55 million, all of which she inherited before marrying her now former husband, Nicholas Granatino. Granatino, who at one point was earning £325,000 a year at JP Morgan but now says he earns a tenth of that as an academic at Oxford University, almost seems poor by comparison. Before they married, he agreed not to claim any share of her wealth, or maintenance. Now, perhaps unsurprisingly, he has changed his mind.

Their prenup was German, written in German and signed in Germany. Were the issue being resolved by a German court, it would have "magnetic" force, as one judge put it. But the case is being decided in the UK supreme court and under the existing law, prenups can only be one factor among many.

Of course the supreme court can change the law – with at least another year before the Law Commission produces any suggested changes to legislation and a lot longer before parliament is likely to act – its decision in Radmacher's case this week will be binding.

But is the supreme court likely to change such a long-standing legal principle, with all the controversy that entails, and without any parliamentary say? The courts may increasingly value contractual automony, but they value fairness even more. And to the extent that prenuptial agreements can have nothing to do with fairness, I doubt they will become "magnetic" in this country any time soon.